Shaving piston skirt

yeah, trimming too much off a piston port motor will kill low end power by giving the gas more room and time to blow back out the intake. I did get reeds already, I've been using them since the beginning of the year. I did end up trimming the skirt though but I made it way too short and the exhaust ended up opening at TDC, so I threw out the piston. The maximum you can trim is about 1-2mm and threw out the old piston. My new one is cut up pretty good as well now, weighs 13g less than a stock piston now, and after a titanium wrist pin will weigh 21g less than stock. Almost no vibrations now, and works perfectly.

Yep, thats the equivalent of opening up the intake port (lowering the bottom). It changes the timing. Reed ports are much more effective IMHO for power but this works as well.